Dr. Russell Marvin heads up Operation Skyhook, which is tasked with sending rockets into the upper atmosphere to probe for future space flights. Unfortunately, all the rockets are somehow disappearing. During the final rocket launching, a UFO lands and the military shoots at it, triggering the destruction of the installation and a cryptic warning from the aliens. In response, Marvin and his colleagues develop an anti-magnetic beam weapon to disable the flying discs. The weapon and the mettle of the populace of Washington, DC are soon put to the test.